Percussion fuse for projectiles subjected to a rotary movement around their axes during their trajectory



Apnl 17, 1928. 1,666,672

A. VARAUD PERCUSSION FUSE FOR PROJECTILES SUBJEC'IED TO A ROTARYMOVEMENT AROUND THEIR AXES DURING THEIR TRAJECTORY Filed June 8, 1926 2Sheets-Sheet l MTV. v I, .1

T a 2 e n 9 5% l 0 f F Z.

va-i117. 1928.

TARY RY A. VARAUD USE FOR PROJECTILES SUBJECTED TO A B0 OUND AXES DURINGTHEIR TRAJECTO June 8. 1926 THEIR Filed PERCUSSION F MOVEMENT AR 2Sheets-Sheet 2 Patented Apr. 17, 1928.

,UVNVITED STATES 1,666,672 PATENT err-"leg v ANDRE VARAUI), OF GENEVA,SWITZERLAND PERCUSSION FUSE Eon PROJEGTILES SUBJECTED' TO A ROTARYMOVEMENT ABOUNI) Tnnm AXES DURING THEIR. TRAJ'ECTORY.

Application ru e June e, 192 Serial No.

The invention refers to percussion fuses for projectiles'subjected to arotary move ment around their axis during their trajectory.

Up to this date the percussion of these fuses has been controlled byimpact either by an inertia effect projecting one of two ignitionmembers (striker or primer) one upon the other, or by the axial'returnmo tion of a striker disposed at the outside of the. fuse point andnormally retained by means of a pin or a spring in its positionprojecting from the fuse point so as to touch the butt or aim before thebody of the fuse does so.

In the case of the first described arrangement it is practicallyobserved'that the inertia effect counted on does not produce itself withsuch an energy and rapidity as will be suflicient to cause percussionwhenever the projectile arrives at the butt in a rather tangentialdirection with the ground as will. often occur in firing with a verystraight trajectory or whenever the projectile falls laterally ontheibutt in'which case the inertia efiect is produced too late forrendering the firing really effective if the impact takes placeon anetwork of barbed or steeple wire, in very humid or marshy grounds, oreven on a pond or the like, because the projectile in such a case isburied .too'deepbefore it bursts.

In the second case referred to, it is possible by a suflicient reductionof the pin or of the spring to increase the sensibility of the fuse sothat the projectile bursts fairly near the surface of the ground, evenif the encountered obstacle offers but comparatively little resistance,but this increase of sensibility is obtained at the expense of safety inthe use of such fuses. In fact it may be stated that in practical usenot only is the transport of such-fuses very dangerous, but that even avery slight error in the caliber of the pin or in regulating the springmay cause the striker to be returned by the resistance of the air and tothereby provoke a premature bursting of the projectile a number ofmeters after its start.

Independently of this defect it is observed in both the cases alluded tothat a great number of failures occur in the firing with a very straighttrajectory, which are :due to the'fact that upon'the impact thepro-'jectile simply grazes the ground and re- 114,428, and in SwitzerlandJune 9, 1925. I

obstacle, an event Which-often produces a torsion of the bar of thestriker and prevents it from freely sliding towards the prlmer. o i

In order toovercome these inconveniences, that is to say inorder toproduce a percussion fuse which, on the one hand, fully Warrants entiresafety during transport and during firing, and, onthe other'hand,secures on the impact a sufficiently instantaneous percussion forcausing the bursting .of the projectile right on theisurface of theround no matter what be the nature of the o stacle met with andthepositionof the projectile on. its arrival, the fuse according to thisinvention is made to comprise at least one member subjected toltheaction ofthe centrifugal power and laterally projecting from the body.of theufuse and remaining in this position regardless of the resistanceof the air during the entire trajectory and which at the end of thelatter will provoke an instantaneouspercussion immediately as the leastpossible resistance displaces it from this projecting position. v j

The drawing shows byway of example a working form of the invention;

Fig. l is an elevation showing the fuse provided with its protectingcap.

Fig. ,2 is a similar view representing the fuse with its protecting captaken off.

Figs. 3 to 6 are axial longitudinal sections showing the fuserespectively before firing, at the moment of firing,.at the momentwhenthe projectile traverses the spires in theicannon, during the trajectoryand finally atthe moment of the impact.

Figs. 7 8 and 9 are transverse sections respectively on the linesVII-VII of Fig.

2, VIIIVIII of Fig. 4 and-IX-IX of Fig. 6.

The Figs. lOto 12 are detail views.

From the Figs. 1 to 6 it willbe seen that the fuse is made from threeportions, a, b, and c, screwed one into the other.

The striker p is mounted axially movable in the axis of the fuse and .isguided by means of a sleeve made in one piece with-the part a. Thisstriker'is normally submitted .to the action'of a percussion spring 7'which is put under tension in the course of manufactureof the fuse andis maintained inthis position until the moment of the impact by means ofa swivelling lever m provided at its free end with a portion m having aninclined plane adapted to enter av notch 12 of corresponding shapeprovided for in the striker 12.

It is easily to be conceived that this notch with an inclined surfaceserves on the one hand to prevent each and every axial displacement ofthe striker in the direction towards the primer when the lever m is inits locking position, and on the other hand is adapted to facilitatethemovement of this lever by the action of the percussion spring 7' as soonas it is freeto the action of the centrifugal power. In order to holdthe portion m of this lever m engaged in thenotch p of the striker p alocking sleeve 9 is made use of in the circular hollow g of which entersa pin m fixed on tlfe lever m lVhen at rest this sleeve .9 is preventedfrom any axial displacement by two cylindrical stoppers n or centrifugalsafety members which are provided for in diametrically opposed positionsand lodged radially with regard to the axis of the fuse. The inner endsof these stoppers come to bear against the periphery of the lockingsleeve 9 whilst its other ends rest on the internal portions of lever Zwhose function will be explained later on.

These diametrically opposed levers Z are arranged in a diametrical slitprovided for in the cap I) and are adapted to swing on a pin 9 fixed inthe cap 1).

Between two shanks Z of each of the levers Z there is provided a releasefinger (Z also oscillating on said pin 9.

Each finger (Z is operated by its lever Z by means of a spring 6 lodgedbetween the shanks Z The part (Z of this finger remains in mesh withacircular groove of the sleeve 9 whilst the notch (Z comes to bearagainst the free end of spring e.

The operation of this embodiment of invention is as follows:

Before beginning with the firingythe protecting cap 71 is removed.

At the departure of the projectile, a cylinder 8 will take under theaction of the inertia effect the active position shown in Fig. 4: andthe levers Z Will, also owing to the inertia effect, remain in theirlodging flush with the body I) of the fuse during the whole linearacceleration which exercises a much more powerful action on said leversZ than the angular inertia moment, derived from the rotary movement ofthe projectile. In other words: since the inertia effect in thedirection of the translation is much greater than the angular inertiamoment, the levers Z conserve their position according to Fig. f duringthe entire duration of the passage f the projectilethrough the spiral ofthe aannon.

As soon as the projectile leaves the mouth the of the cannon andtherefore the linear acceleration has reached its end, the centrifugalpower causes regardless of the resistance of the air, the spreadingapart of the lovers Z which will take the slant position sion so that itwill be'ready to function at l the moment of impact irrespective of thenature of the obstacle metwith and no matter what is the position inwhich the projectile arrives at the butt.

The fuse having thus been put under tension nothing will hinderanylonger the axial I advance displacement of the sleeve 9 and thisdisplacement will take place at the end of the trajectory in one of thefollowing man ners:

1. Under the action of the inertia effect, which tends to throw thesleeve g forward if the projectile by its point strikes a relativelyhard obstacle.

2. Under the action of the folding of the levers Z transmitted throughthe fingers d, in the case that the levers themselves are the first tomeet the said obstacle, regardless of the fact if the latter offers butalittle resistance as for instance would be the case if striking barbedwire or the like.

3. Under the simultaneous effect of both of these mentioned actions ifthe obstacle met with is a liquid mass, or very soft ground, as marsh orthe like, in which the projectile would easily enter if its burstingwere not operated nearly upon grazing the ground owing to theconjunction of the inertiaeffect acting on the mass of the sleeve 9 andthe foPding of the levers which in their .spread position offer to theobstacle a contact area which is great enough for securing the 1 smallshanks of the two liberating fingers d to be operated by the two shanksof the relatively very long levers which they constitute.

4:. Under the simultaneous action of the inertia effect operating on thelevers in the direction of folding a-nd the rebounding effect whichtends to throw the sleeve 9 forward when upon arrival at the butt theprojectile falls on its head.

I claim as my invention:

1. Percussion fuse for artillery projectiles submitted to a rotarymovement around their axes during their trajectory comprising a controlmember submitted to the action of the centrifugal power in such a manneras to be adapted to become laterally standing out from the body of thefuse and to remain in this standing out position during the wholetrajectory, regardless of the action of the resistance of the air, anoscillating memher for locking the striker constituting a lever adaptedto swing in a plane perpendicular to the axis of the fuse and which isprovided with a pin operating in the bore of a locking sleeve mounted tobe axially movable in the direction of the advance of the projectile andconcentric with regard to the striker, said sleeve being held in itsactive position against the action of a percussion spring during thewhole trajectory of the. projectile by a device controlled by thedisplacement of said control member standing out from the body of thefuse during the trajectory of the projectile.

2. Percussion fuse according to claim 1, in which a centrifugal safetymember is mountcd in a radial slit for immobilizing the said lockingsleeve in its active position until the moment in which the projectileleaves the mouth of the cannon, said safety member being adapted toemerge under the action of the centrifugal power through the said radialslit.

3. Percussion fuse according to claim 1, in which a centrifugal safetymember is mounted in a radial slit for immobilizing a locking sleeve inits active position until the moment in which the projectile leaves themouth of the cannon, and in which the control member stands out from thebody of the fuse during the trajectory of the projectile and is adaptedto hold the said centrifugal safety member in its active position durinthe passing of the projectile through the spires of the cannon.

1. Percussion fuse according to claim 1, in I Which the control memberstanding out from the body of the fuse during the trajectory of theprojectile is constituted by a lever, a finger being provided which isadapted to become operated by the folding of said lever at the end ofthe trajectory When it meets an obstacle, in such a manner that alocking sleeve is sufiiciently axially displaced as to allow theliberation of a swiv'elling member locking the striker, a spring beingarranged between said finger and the lever in order that upon theprojectile leaving the mouth of the cannon, the spreading out of thelever causes the device for putting it under ten sion to be operative.

In testimony whereof I aflix my signature. 7

ANDRE VARAUD.

